Whoa, whoa, whoa! Move over John Le Carre! What research! What psychology! What style!
Yes, what style! What deft shifts between time and reference frames! What masterful prose! As complex as the best of Le Carre, and yet not as dense. Not sure whether to recommend this, or Leaving Berlin, or The Accomplice, as the place to start. But do not start with Istanbul Passage, which by comparison is relatively weak: author just does not have the background on Turkey to give us something as rich and complex as his books set in postwar Germany. But his Germany is superb. Superb.